Lately Ive been having a ton of fun
with audio. Most of the fun Ive had revolves around building,
modifying and tweaking equipment, primarily of the tube persuasion.
Ive always been a do-it-yourself kind of guy, and now finally,
armed with just enough knowledge to be dangerous, Ive applied
my DIY tendencies to my audio habit.

This isnt a true DIY article in that
it really doesnt tell you exactly how to do anything, except
maybe how to get in touch with the manufacturer of the product
reviewed here and get a kit for yourself. Rather than provide
specific instruction, it is meant to encourage readers to try
their hand at DIY audio with a relatively simple project. DIY
audio is fun, challenging and oh, so rewarding. It is a big rush
the first time you fire up a component that you built yourself
and have it perform splendidly . . . but thats when the
fun just begins. Once you have built something like this tube
preamp, I guarantee that you will soon be overcome by the urge
to tweak it and modify it.

Here, I will outline a particularly fun
DIY audio project that Ive been working on. By talking
about it, Ill hopefully provoke some thought, maybe even
action, on your part.

Would you like to build a $99 preamp?

No, this isnt an ad from the classified
section of Popular Mechanics, circa 1973 . . . this is
for real. Welcome to true, entry-level, hard-core DIY tube audio.
Sound interesting? It is.

Over the past fours years or so, a down-to-earth,
way smart, innovative, music-loving tube audio dude, reverently
nicknamed Doc Bottlehead (aka Dan Schmalle) by his audio buddies,
has been publishing a little magazine called Valve. I
use the term "magazine" loosely, as the look of this
mini-mag is decidedly retro, right down to the photo-copy and
staples motif it has going. The magazine looks homebrewed, as
do the projects you build after reading it. Lets just say
that Valve is as visually different from Stereophile as Jesse Jackson is politically from Ralph Reed. Valve is a very cool magazine. Despite the low-tech appearance, however,
the content is absolutely cutting edge  were talking
waaaaaaaay out there. The designs these guys come up with are,
um, unique. For example, how bout a one-watt, single-ended
power amp using an output tube youve probably never heard
of? Is that wacky enough for you? I thought so.

Doc Bottlehead and his tube audio compadres
have come up with a few different DIY kits that they make available
to subscribers of Valve, or anyone else for that matter,
and who would like to try building their own equipment. The kits
are sold under the brand name Electronic Tonalities, which is
the kit sales division that was formed by Doc to distribute his
products. Doc has a website at http://www.bottlehead.com and can be reached by e-mail at bottlehead@bottlehead.com.

Electronic Tonalities sells two amplifier
kits (both monoblock-based, one using the 6DN7 output tube and
one based on the venerable 2A3) and one line-level only preamp
kit called the "Foreplay". Youre probably wondering
about that name. Well, Docs first (and most famous) kit
was called the Single Ended eXperimenters amp, or S.E.X.
amp for short. In its current iteration, the S.E.X. amp kit is
a pair of DIY 5-watt monoblock amps, all triode, single-ended,
for $399/pr! Hundreds of those babies found their way into the
hands of hungry little tube audio DIYers who really wanted
to build something without breaking the bank.

With that as background, fast forward to
1998 and the release of the "Foreplay" preamp kit.
Virtually all of the Electronic Tonalities products are named
from the "play-on-sex-words" theme, hence the Foreplay
preamp. A line from the advertising copy states that "S.E.X.
is always best when preceded by Foreplay". These names will
probably prevent the Electronic Tonalities products from becoming
too mainstream, but then again, these products arent going
to be sold on the shelves of your local Electronics Mega Mart
anytime soon, so maybe being out of the mainstream is fine with
Doc at this point. The whole naming thing is right in line with
Docs philosophy of not taking the kit business too seriously,
although the quality and innovation of the designs are as serious
as can be.

How much was that?

The Foreplay preamp kit costs $99. Yep,
thats two digits. It comes complete with all components
you will need to have a functioning tube preamp at the end of
the project. Thats right around the cost of dinner for
two in San Francisco at one of our many fine restaurants, which
is a decent way to spend an evening. For about the same cost,
the Foreplay strikes me as good entertainment for many years,
heck, maybe even a lifetime. Ill save the dinner money,
take the Foreplay and throw a box of macaroni & cheese on
the stove, thanks very much.

O.K., $99 is where you start, but if you
also want the wood base kit for the preamp (recommended by yours
truly), it will set you back another $15. Even then, were
still talking about a super-duper, you-have-to-be-kidding level
of affordability.

Heres a little good news/kind-of-bad
news: The kind-of-bad news is that the passive componentry
in the kit is quite basic. Duh. What did you really expect for
$99? The good news is that, should you decide to explore other
"designer" components by tweaking and modifying what
was sent with the kit, you are then doing exactly what Doc hoped
you would do. The object of DIY audio is to build something,
change it around, have fun and inhale lots of solder fumes while
doing so. Dont get me wrong, you can build the preamp with
exactly the parts supplied, and you will be very, very happy.
But change an output capacitor here, a resistor there, beef up
a few power supply caps, and voila, you have perhaps the ultimate
budget preamplifier.

Flawless Instructions = DIY Success

Did I mention that anyone can build this
preamp? The step-by-step directions are flawless. Even if you
have no idea how to set the clock on your VCR, you will still
be able to build the Foreplay. Heck, assuming it isnt one
of the stupid breeds, your dog has an excellent chance of successfully
constructing this preamp. Not only is the assembly manual complete,
but it also includes lots of safety tips at the beginning, along
with post-construction resistance and voltage readings that you
reference once your wiring is complete.

Hows it look? Not bad, not bad at
all. It is a compact design with all circuitry built on a pre-cut
11" x 7" sheet of brushed aluminum. You have the option
of spraying the aluminum with a clear finish for that natural
look, or you can be like me and finish it with primer and a couple
nice coats of flat black spray paint. I also finished the base
with black wood stain and a satin clear urethane  I think
it looks absolutely cool. Its retro and high-tech at the
same time.

Features? No, not really, but it does have
all you really need for a preamp  volume (individual left/right
controls) and input switching (three selectable inputs). Forget
the highly sought after remote control  you couch potatoes
will have to burn a few calories and walk to the preamp to change
volume. Besides, this isnt a remote control kind of preamp.
Its meant to be hands-on in every respect.

The Foreplay uses the ubiquitous 12AU7
preamp tube  nothing fancy, nothing exotic. While I would
rather build a preamp around either of the 12AU7s cousins,
the 6SN7 or the 76, those arent the tubes that Doc chose
for this design, preferring instead to ensure that the tube was
readily available and easy to work with. As part of the tweaking
process, Ive experimented with a bunch of different New
Old Stock (NOS) brands/varieties of the 12AU7 (5963, 7316, 5814/A,
etc.). The process of experimenting with all these different
tubes is called "tube rolling", and its a hoot.
Imagine being able to "tune" the sound of your system
by simply changing tubes in your preamp  a tweakers
dream for sure. Lets just say that after lots of listening
and switching, Ive found a few 12AU7 type tubes that really
kick tail, but of course Im not at liberty to disclose
those here lest you all go out and corner the market on my favorites.

But how does it sound?

This is where reviewers (Ive been
guilty of it myself) normally break into a blow-by-blow account
of the superlative subjective sonic attributes of a piece of
gear. To do this, they use multiple references to all their favorite
songs that were playing when they had their life-changing aural
experience. If you need that type of review right now, please
dig out your latest WhatchamaAudio and check out what
they have to say about the latest, greatest $3,600 "real
world" preamp. Im not going there.

What I am going to say is that Ive
had a bunch of different preamps, tube and solid state, through
my system. To use a tired phrase (but the only one that I can
think of right now), if you told me tomorrow that the Foreplay
would be the only line-level preamp that I could use from now
to eternity, I would not be the least bit upset. Its that
good, folks. They key is that this is an incredibly simple, pure
design  short signal paths, point-to-point wiring, compact
layout, direct coupling of the amplification stages, etc. If
you subscribe to the general theory that simpler is better, you
will appreciate the logic and beauty of the Foreplays design.
Personally, I fall squarely into the "simpler is better"
camp  it took me a while to get there, but thats
where I am now. After lots of experimenting, I believe that keeping
things simple will almost invariably result in better sound.

Is this the best preamp available? Are
you kidding? Is this the most sensible preamp available? Well,
you could probably construct an argument to support that. For
lots of people, it may very well be. My guess is that many of
you, deep down, wish that you could go this direction, but are
afraid to tell your audio buddies that you use a preamp that
costs less than one meter of their favorite interconnect. I understand
where youre coming from, but hey, take a $99 chance and
live on the edge.

Look, this isnt an article about
high-end audios ultimate preamp. Its about the fun
of getting your hands dirty and building a preamp that just happens
to have a shockingly low price and an equally silly high level
of performance. Its about the satisfaction of DIY audio
and listening to something you built yourself. Is this the last
preamp I will ever build or own? Thats highly unlikely.
In fact, the success of this project will surely lead me to try
constructing other designs. To sum up, however, I could not be
happier with the Foreplay preamp and how my project turned out.
It was, as Ive said before, lots of fun. Isnt that
what this hobby is supposed to be about?

- Paul Knutson -

Note:
Watch future issues of Secrets of Home Theater and High Fidelity
for our on-line Tube Preamplfier Project. We will do a series
of articles that chronologically document (with photos!) the
construction of a transformer-coupled, line-level preamp using
a medium-mu triode output tube. This preamp will be a state-of-the-art,
very high performance design, yet still be simple to build as
you follow along with our project. This is going to be an exciting
project for all of you who want to push the envelope in DIY tube
audio. Stay tuned!

Upgrade
Your $99 Tube Preamp Kit

So, I'm assuming (fingers tightly crossed)
that you followed my advice and took your best shot at building
the Foreplay preamp. If you did, I'll bet it was a successful
project and that you're already grooving to the wonderful sound
of tubes -- maybe even as you read this. Heck, there are likely
some brave souls out there that have already tinkered around
with the parts in the preamp to see what improvements can be
rendered by tweaking an already rock-solid circuit design. If
so, congratulations! You have the first symptoms of audio DIY
disease and it's among the most pleasant of all afflictions.

As pleased as you already are with the
sound of the basic Foreplay, you are likely curious about the
upgrade kit for the Foreplay, not unexpectedly named Anticipation,
that Doc Bottlehead advertises at his website. "If Electronic
Tonalities can do this for $99, what would happen with another
$75 investment?" you wonder. Well, wonder no more
read on and find out.

What is Anticipation?

Simply put, Anticipation is a major performance
upgrade for the Foreplay kit preamp. It goes well beyond the
typical tweaking of passive parts into the realm where the operating
characteristics of the circuit are changed in a big way. The cost of Anticipation, in kit form,
is $75 and includes everything you need save a couple feet of
hook-up wire. You are free to use your wire du jour for this
project, but make sure it's small gauge -- I recommend 20-26
gauge solid core wire. Inside Foreplay there are places where
many wires meet at common junctions, such as the ground. Installing
Anticipation only makes these connections more crowded so don't
overdo it with 14-gauge multi-strand or anything silly like that.

The circuit technology behind the Anticipation
upgrade is based on something called C4S, which is short for
Camille Cascode Constant Current Source. John "Buddha"
Camille is the person responsible for the design of the C4S concepts
applied to Anticipation. Buddha and Doc Bottlehead are buddies.
Between them, they come up with some wickedly effective ways
to jointly-implement their ideas.

I'm not going to confuse beginners or insult
experts by trying to explain exactly how the Anticipation upgrade
and C4S work. That would be folly. To be honest, I don't really
understand it myself, but I'm trying darn hard to learn. To summarize,
by replacing four fixed-value resistors in the circuit (plate
load and cathode loading) with what are known as Active Loads,
(which are a variety of resistors, transistors and diodes mounted
and soldered onto a mini circuit board), you greatly increase
power supply isolation and linearity. The end result is a tube
(and preamp, for that matter) that is operating more optimally
and happier doing its job.

The obvious goal of the Anticipation upgrade
is better circuit performance, and thereby better sound, from
your Foreplay preamp. Is it successful? I'm sure you can guess
the answer already, but play along for a moment while I talk
briefly about the installation of Anticipation, after which I'll
move quickly to the punch line.

Installing Anticipation

There's no need to do a step-by-step instruction
of how to install Anticipation -- Doc B. does a great job of
that as usual with the Anticipation Installation Guide. I'll
limit my thoughts to a few basic observations.

If you've already done it, you will agree
that building the Foreplay was really very simple. This presumes
that you first practiced your soldering and that you also had
the patience to followed the clear directions closely.

Installing the Anticipation upgrade was
slightly more difficult than building the Foreplay, in my opinion.
Remember, I am virtually still a novice (maybe intermediate)
so if you are an experienced solder slinger my opinion of difficulty
should be taken with a grain of salt. The premise with Anticipation
is to challenge the DIY builder just a little more than before
as his/her skills develop and interest grows. Bottom line is
that with care and patience the Anticipation installation is
nothing to worry about.

As a brief aside, Doc and I have exchanged
e-mails on the topic of whether to install Anticipation when
you initially build the Foreplay, or whether like me you wait
and do it at a later time, after you are accustom to the way
the basic Foreplay sounds. Installing Anticipation during the
initial build is simpler, but my strongest recommendation is
that you wait to install it later. Only then will you fully appreciate
the improvements. Believe me, it is worth installing later if
only for the sheer joy of hearing a true, effective, major circuit
upgrade for the first time. You will smile when you hear it,
and smiling makes you feel good.

How Does Anticipation Sound?

In terms of whether the Anticipation upgrades
the sound of the Foreplay, I guess I've let the cat out of the
bag with the final two sentences of the previous paragraph. Yep,
it sure does. Oh, so rarely in audio does an upgrade do as advertised,
but this is one of those times. Too often an alleged "upgrade"
by a major manufacturer will encompass some new hookup wire and
a detachable powercord -- welcome to "Mark II" and
thank you for the additional $800! Not here, guys and gals
this is the real deal.

For the $75 investment in Anticipation,
plus your time and energy, you take the Foreplay preamp to new
sonic territory. To my ears, in my system, the Anticipation upgrade
resulted in the following improvements:

1. Improved definition and impact in the bass. This was the most
noticeable improvement and addressed an area where the basic
Foreplay has a slight weakness;

2. A greater sense of space and distinctness
of individual instruments within that space;

3. More swing, heft and weight during crescendos
of any kind. In all, it was a sense of the power amp delivering
more power to the speakers. Obviously the power amp wasn't changed,
but it sounded like it;

4. More gain, which I didn't need, but
some of you may; and finally,

5. Sharper transients on percussive strikes
of any kind.

I am not a huge classical music fan, but
there are some emotionally stirring classical works out there
that any music fan can appreciate, and until the Anticipation
upgrade I wasn't quite satisfied with the way my system did that
stuff. I am now. For all other types of music, I must say that
I shake my booty and tap my feet just a little more now than
ever before. These are excellent barometers if there ever were
any.

Final caveat, though you can hear the improvement
from Anticipation right away, give the Foreplay about 30-40 hours
of use after installing Anticipation to allow it to break in.
Save your critical listening until that point. Speaking from
experience, you need to give it this much time and you will be
glad you did.

Summary

The Anticipation upgrade is a winner! It
wins by not only being effective for the measly asking price,
but it also wins on absolute sonic terms as well, irrespective
of price.

I dare you, no, make that double-dare you,
to build the Foreplay, add the Anticipation upgrade when appropriate,
then take that baby to your next local audio club meeting. Don't
tell anyone about it first, just play it. E-mail me and let me
know the reactions you get when you finally tell the numerous
dumbfounded that 1) you built it yourself, and that 2) it cost
less than $200, all in. I need a good chuckle to brighten my
day now and then.

Doc Bottlehead and the folks at Electronic
Tonalities have been busy as heck over the past number of months
-- they've released a parallel feed version of their 2A3 amp
kit, a 300B amp kit, an interconnect kit and a host of other
goodies and do-dads for the hardcore, and beginner, audio constructor.
More products and projects are in the works.

These are pretty exciting times if you
are into this sort of stuff, which I most certainly am. Who knows,
there may even be other upgrades for the Foreplay available in
the future. If so, I'll be in line to get my hands on 'em and
tell you all about it. In the meantime, I've got some music to
listen to.

Without being an electronics designer, I had no problem
building the Foreplay Kit other than burning up my cheap soldering iron. See
the Foreplay “Specs” download for more information about my first
experiences with this preamp at: http://www.bottlehead.com/et/et.html.
I suggest assembling the kit slowly and double checking everything.

My background is in film and video production. While
some audiophiles only listen to find perfection, sometimes less than
perfection can be useful to me if it creates a new sound signature that
enhances the media experience by producing a unique emotional tone. So I am
interested in the unique sound signatures of different electronic parts.

What
follows are descriptions of the different sound signatures for capacitor and
tube substitutions in the Foreplay Preamp which has the Anticipation
modification installed. Comments are also made about how two different
speakers affected the listening experience.

Listening
Material

My
test music was the Sade Love Deluxe album's "No Ordinary Love" and
"Cherish The Day". Also used was the Bonnie Raitt Luck of the Draw
album's "I Can't Make You Love Me". These tunes include female
vocals and much bass instrumentation with a soundstage that was probably
created artificially by a mixing console.

For
acoustic instrument sounds a jazz instrumental was auditioned,
"Children's World" by Maceo Parker. It featured saxophone, bass, and
drums. I don't know the recording conditions, whether live (in front of an
audience) or studio.

Sound
Equipment

Sound
equipment was an Apple 9600 computer CD player and the Foreplay-Anticipation
preamp with shunt pots. The amp was the Doctor B modified Zen SV83 (about 2.25
watts). The Zen's Svetlana SV83 output tubes ($4 each and similar to EL84s
which can substitute with some modification) I call “candles” since they
look like short little candles rather than like a big output tube.Check out Svetlana tubes http://www.svetlana.com/.
The Zen has an Anticipation upgrade, and I added shunt pot resistors to the
volume control pot.

A
"shunt pot" is a technique which places a resistor in parallel with
the volume pot. This resistor is a higher quality sonic path than an
inexpensive volume pot. Since part of the signal goesthrough this high quality resistor directly into the preamp,
that part of the signal will be higher quality and upgrade the overall sound
quality of the preamp. Thus, when using an inexpensive volume pot, some of the
sonic noise from the inexpensive volume pot materials is bypassed. Purist
designers who concentrate on producing only the simplest circuits that use
only the highest quality components probably won’t like this technique, which
might be said to confuse the sound path. But the technique is a reasonable low
budget modification that should normally provide a little sonic improvement
without adding significant noise.

Speakers were 86 dB efficient NHT
(Now Hear This) Super Zeros ($230 per pair) pictured in black. A Cambridge Soundworks powered subwoofer was used with the Super Zero speakers since they only
go down to about 100 Hz.

Also used were 97 dB efficient
British made Lowther speaker drivers type PM2C mounted in bass reflex cabinets
constructed by David Dicks ($1,300 combined cost). The driver is pictured
(below, right) with
the white cone. Lowther drivers are accused of having no bass, but with the
David Dicks bass reflex cabinets, they do have bass, though it is rolled off by
about 6 dB below 100 Hz. Lowthers are said to be driveable on 2 or 3 watts, but
you will need 7 watts or more to hear all the bass that these cabinets are
capable of and no more than 30 watts are needed with a good amplifier.

I
am told that Lowther drivers have a 10 dB peak in the 2 kHz to 10 kHz frequency
range. This peak was great to compensate for older designed tube amps that
attenuated high frequencies (due to poor transformers etc.) but not great for
most modern designs that lack the problem. A fix for this peak is
given later. Also, Lowthers don't have the best soundstage since the high
frequencies "beam" in a narrow pattern off the fan shaped inner
mounted whizzer cone. So why use them?

I
use
Lowthers because they display almost any change made in sound equipment due to
their special design characteristics.Lowthers
have such a large magnet that only 1 millimeter (0.03937 of an inch or about
1/25 of an inch) of driver travel produces a nominal 97dB. Other drivers have
a 13mm (1/2”) to 39mm (1 1/2”) driver travel. So clearly Lowther had
something else in mind when they decided to use the most powerful magnets in
the industry, at 17,000 gauss plus, with only 1mm of travel!

Designed
as a single full range driver, Lowthers require no crossover though I would
suggest using one (see below). Thus, some Lowther owners use no capacitors or
inductors that would otherwise affect sound purity. I experimented by placing an inductor in
line with the Lowther driver. The effect was to create a false sense of
spaciousness, a spaciousness created by the “sound” of the inductor and
not by the source musical signal. I now recognize this fake soundstage
characteristic in most commercial speakers that I audition. It isn’t
really a bad sound, just a sort of unmistakable sonic signature that makes it
sound like the music was created in an acoustic space that had walls and thus
has a significantreflective
component.

It's due in part to phase shift caused by the inductor (or capacitor).

Phase
relationships are potentially better preserved with a single driver producing
all the sound motion. Lowther drivers do create a soundstage though of lesser
size than that of other great speakers.

If
a parallel notch filter is added to remove the 2 kHz - 10 kHz frequency peak, then
the driver’s sound staging is better, though the sound is then colored by the
capacitors, inductors, and resistors used in the filter network. See "The
Loud Speaker Design Cookbook 5th edition" page 120 & 121, section 7.70
"Response Shaping Circuitry" for design information on parallel
notch circuits. I would like to thank James Carol, speaker designer, from
Knoxville, Tennessee for helping me build my first parallel notch filter.
Cutting this peak adds needed flattening to the speaker frequency response
curve and gives a few inches greater width to the "sweet spot" where
the speakers provide center image. For my ears, using some form of filter to
cut this peak is necessary for long term Lowther listening enjoyment. With the
filter added, I feel like I'm listening to a pair of $2,100-plus purpose built
high-end
speakers, though I only paid $1,300 for them.

Last,
but maybe most importantly, Lowther drivers are
"fast". After you've heard a snare drum through the Lowthers, you
will be hooked. For probably the first time, you will hear the individual drum
stick beats that were slurred by other speakers, though you didn’t realize
it. There is an old saying from Formula One racing, "The motor is as fast
as the bee's knees." If you want to hear the speed of the bee's knees, then you'll probably have to try Lowther full range cone drivers or a great
set of horn speakers. Hearing Lowthers for the first time is a new experience
for most people, since they have properties of both cone and horn speakers.

To be fair, this version of a Lowther speaker, with its
single driver surrounded by a bass reflex box that gives out its bass 6 dB or
so below the level of the the mid and upper frequencies, best plays the music
of small jazz groups and individual vocals. Any single driver-based speaker
has a limited amount of magnet-to-voice-coil-area in which to transfer the
signal's complexity. Rock and orchestra music with their tremendous complexity
of signal and significant bass seem to demand more than a single driver can
re-create. But for hearing music that emphasizes the tone color and speed of a
few individual instruments and/or vocals the Lowthers give a tremendous amount
of intimate detail.

The
Foreplay Preamp produces beautiful sound with my modified NHT Super Zero
speakers. Although this is a budget system, it reproduced the most important
sonic elements that can be found in even multi-thousand dollar high-end audio
systems. But, on the ruthlessly revealing Lowthers, the stock Foreplay output
capacitors sounded dry with a narrowed sound stage. The output capacitors are
directly in the sound path, so they are the most important capacitors in the
circuit as far as
sound quality is concerned.

This
is an easy modification that anyone can do. Buy two non-polarized capacitors.
Desolder the capacitor lead connected to each of the preamp’s RCA output
plugs. Desolder only one end of the connected capacitor lead at a time so that
you don't forget where the other end is attached! Solder the new capacitor’s
lead to the RCA plug for each channel. If you forget where to connect the
capacitor, just look at the Foreplay schematic or step-by-step instructions.
Due to their flexible lightweight leads, the Hoveland (yellow) capacitors,
spoken of later in this article, need a mounting system of heavy double sided
tape or a physical mount as shown in the picture. I had allowed them to
“hang loose” previously, only to find later that they had broken loose at the
RCA plug solder joint.

Please
see the pictures of the stock Foreplay (first part of this article, by Paul
Knutson), as well as the picture of a Foreplay
with Anticipation upgrade and Hoveland yellow capacitors (photo below, right).

Lowther listening showed that, with
the Solen caps, the analytical dry nature of the metallized polyester capacitors was
gone. The physically larger Solen metallized polypropylene capacitor material
gave much greater richness on vocals. Bass depth and volume were vastly
improved. Sound stage was also significantly increased in width and depth. Not
bad for just changing 1 dollar capacitors to 3 dollar ones.

With
a less accurate speaker like the NHT Super Zeros, the dryness condition caused
by the stock capacitors hardly showed up at all. I rather liked the
"dark" sound of the stock capacitors on the NHTs. By limiting some
of the lower power level high frequency information, they gave the sound a
mystic quality of "dark black" quietness with music that protruded
out of that darkness.

So
is it worth the trouble to change to Solen capacitors when using speakers less
advanced than the Lowther speakers? Yes, very much so. The NHTs were quite
able to give greater satisfaction, including a larger sound stage, from the
capacitor change. The Super Zeros just don't reveal the full effect of the
component change as do the Lowthers.

Now
back to the Solen sound effect.

The Solens give midrange and highs
with a silky smoothness and detail similar to the most expensive sound systems
that I've heard, and they resolve mixing effects better. For example, in much
alternative rock, the vocal gets lost as it mixes in with the guitar. But, with
the Solens, the vocal separates just enough from the guitar chords that the
words become intelligible, yet without losing the creative effect of having
the vocals and guitar sonically in the same space. And the Solens gave some
nearly free ($) bass, apparently about 6 to 9 dB more power. Thismakes sense because the Solen's physically larger capacitor
body passes more low frequency power and current.

The
sensual beauty of Sade's voice on the album Love Deluxe with the cut
"No Ordinary Love" is reproduced excellently with Solens. The bass and
female vocal on this particular song is one of the best test audition tracks
that I've found for a studio type sound mix. The bass guitar sound at the
beginning is hauntingly deep. The vocal is smooth. The rest of the
album is also excellent (a rare great album).

The
Solens are really inexpensive at about $3 each, yet they give the sense of a
$100 upgrade. The swap out of the stock capacitors for the Solen capacitors is
probably the most important thing I've ever done for my system short of buying
a brand new piece of equipment.

Next, I tried American made Hoveland MusiCap (yellow colored) 2.0 µF 400
volt polypropylene film and conductive foil capacitors at $22 each. This may
sound impossible after reading all the positive statements about the Solens,
but yes the Hovelands are better and by a great margin. While everyone remarks
that treble loses its harshness when a quality capacitor is used, with the
Hovelands inserted, the bass immediately improved also. When the electric bass
player on Bonnie Raitt's "I Can't Make You Love Me" pulled the
string, I could practically see his fingers move. With the Solens inserted,
the bass notes seemed to quit early rather than naturally decrease in volume.
The feeling received from the Hovelands is that the bass note attack and decay
is “rolling” and sustaining so naturally that you think you're hearing a
private performance from a live band in your room.

With
Marceo Parker's "Children's World", the acoustic decay,the "roundness" of the instrument such as the bass guitar,
and the accuracy of the rhythmic speed, increased as each successively better capacitor was installed. With the Hovelands installed,
a Bottlehead forum regular and Dixie Bottlehead principle remarked that the Foreplay-Anticipation would be excellent
competition for many commercially available preamps priced at $4,000.

Comparison
of the Three Sounds

To
compare the three different capacitor sounds, the stock capacitors give the sense of a dramatic
live “driving” band playing in front of me in a room with okay acoustics.
TheSolen capacitors give the
sense of a live band playing in front of me in a room with good acoustics
with band members playing great quality instruments. The Hoveland capacitors
give the tone quality of even better instruments, in a room with nearly
perfect acoustics, and the sense that I am fortunate enough to be sitting
in exactly the most acoustically perfect position in that room and am
experiencing no off-the-wall-reflection based frequency cancellations!

Capacitor
Materials

It
has been my experience that the material used to build a capacitor affects the
sound according to that material’s natural sound dampening characteristics.
This was especially noticeable when I took a trip to a famous high-performance
speaker manufacturer who used a multi-order crossover network (thus passing
the signal through many different capacitors). They used polypropylene
capacitors which gave percussion instruments the distinct sonic character as
if they were being hit against a plastic pail. High-frequencies seemed to die
away as though they were being reflected off a soft plastic wall.

To
summarize the capacitors and their “material sounds” that I’ve heard: Physically, much polyester fabric seems scratchy when you run your
hand over it, and the sound of polyester capacitors on a highly revealing
system can sound harsh or etched, as if the high frequencies are being
scratched across cloth. Polypropylene (a plastic material) capacitors
give a sound damping somewhat like what can be heard by rapping your
knuckles against a polypropylene water pail. Audio Note paper-in-oil
capacitors are made of a material that one would think of as a gooey slippery
soft combination, and the sound out of these capacitors tends to be distinctly
laid back (slower attack envelope, lower slew rate) and softer, yet with a
great smooth sense of beauty. Hoveland capacitors use a polypropylene film and
conductive foil combination that comes somewhere in between the others in
physical properties, and also has arguably the best combination of sound
qualities. I would sell shares of may favorite stock to buy them.

Tube
Substitution

You will have to install the Solen capacitors, or
better, to fully judge the sound signature of different tubes in the preamp
stage. When swapping tubes: 1) Turn the preamp off before removing or
inserting tubes; 2) Use a thick cloth to cover the tube to avoid being
burned; 3) Grasp the tube near its base, then pull the tube out slowly, rocking it only
a little to loosen it as needed; and 4) Replace a tube by firstpositioning each tube pin in the correct pin hole, and only after your
eyes have seen that each pin is pressed into a pin hole, begin pressing straight
downward while rocking the tube the minimum necessary (the tube may need no
rocking) until the tube bottoms out on the socket.

I swapped the stock Foreplay Sylvania 12AU7A
tubes for RCA 5963 NOS (New Old Stock) tubes ($6 each).My
5963 RCA tube source was Robert Silk of Silk Electronics at (801) 583-6616 in
Salt Lake City, Utah. Robert will give you his opinion over the phone, which is
quite a useful service to those of us who experiment.

My
first sound notes for the 5963 were,"There is a new clarity, more micro and
macro dynamics. Where instruments before were mixed in together, they are now
separate. Quiet surrounds instruments rather than noise". But as time passed, my
notes changed to, "The 5963s cut some of the “air” around instruments, thus
the sound is a little darker. They seem to suppress some miscellaneous phase
shifting confusion, thus making instrument positions more stable. They seem to
eliminate some noise, they sound cleaner, and this cleanup effect also brings
out a sense of rhythmic drive".

Ultimately
I realized that there had been a loss of detail which made the tube seem
cleaner and thus "better" for a while. So it goes when a component
change is made, what at first sounds better may later reveal itself as just
different or even a worse sound. In this case, both capacitor and tube changes
made the little Foreplay Preamp a real joy to listen to.